Rear bumper



FIG. 1 is a front perspective view of a rear bumper showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a left side elevational view, the right side elevational view being a mirror image; and,

FIG. 4 is a top plan view thereof. 

CLAIM The ornamental design for a rear bumper, as shown and described. 